A National Intelligence Council report projects that by 2030 the U.S. will become energy independent and that China will overtake the U.S. as the world's largest economy.

The report warns that any challenge of China's communist leadership… (Associated Press )

WASHINGTON — Majorities of people in most countries will achieve middle-class economic status by 2030, but the effects of climate change, an aging global population and anti-government movements in authoritarian nations such as China could cause upheaval in economic and political systems.

The predictions come from a forward-looking study by the National Intelligence Council, which every four years analyzes key trends and projects their implications 20 years into the future.

The United States is likely to remain "first among equals" among world powers because of the legacy of its leadership role and military power, according to the report.

No other global power or international order is likely to replace the United States' primacy, it said, even though in terms of overall power — economic output, population, military spending and investment — Asia will surpass North America and Europe over the next two decades.

"The context in which the U.S. global power will operate will change dramatically," stated the 166-page report, titled "Global Trends 2030: Alternative Worlds."

In a dramatic shift from previous reports, it projects that the U.S. will become energy independent because of abundant shale gas deposits now accessible with hydraulic fracturing technology, known as fracking. That is likely to reduce America's dependence on energy sources from unstable regions of the world.

The report assesses that China will overtake the U.S. as the world's largest economy as measured by national output, but notes that the growing wealth there may spark a popular yearning for multi-party democracy. It warns that any challenge of China's communist leadership could lead to political turmoil, however, and upend the global economy.

In a best-case scenario, the study said China may undergo gradual political reform and work closely with the United States to usher in a period of global political stability and economic growth.

A worst-case projection has the United States turning inward and the European Union unraveling, while corruption and social unrest stall growth in the world's largest countries, China and India.

The study described the expected growth of the global middle class as a "tectonic shift" that will require sharply increased production of food, water and energy, and may lead to scarcities.

"For the first time, a majority of the world's population will not be impoverished, and the middle classes will be the most important social and economic sector in the vast majority of countries around the world," the report noted.

But increasing global temperatures and rising seas may disrupt rain patterns and agriculture, and many countries probably will face food and water shortages.

Aging nations such as Japan, with fewer workers supporting a growing number of retirees, will face an uphill battle to maintain living standards. It projects that Russia will see its population fall by as many as 10 million people, and will continue a slow decline in global influence.

With the rapid expansion of new technologies, individuals will be empowered as never before, the study said. But the same trends have the potential to aid terrorists and criminals, who will have access to new methods of attack.

Terrorists could use drone aircraft to deliver biological toxins, or launch major cyber attacks to disable infrastructure, the report warned. On the other hand, it projected that the war against Al Qaeda is likely to be over by 2030.

"The current Islamist phase of terrorism" probably will recede just as other terrorism movements have faded away, including anarchists in the late 19th century, post-World War II anti-colonial movements and violent New Left groups in the 1970s.

Some 15 countries are at high risk of "state failure" by 2030, the study said, including four where the Obama administration is targeting Al Qaeda militants — Afghanistan, Pakistan, Somalia and Yemen.

The global trend reports tend to be broad enough to account for almost any outcome. None of the scenarios is inevitable, but they have occasionally proved prescient.

In 2000, a year before the Sept. 11 attacks, the report discussed the threat of large-scale terrorist attacks.

"Such asymmetric approaches — whether undertaken by states or non-state actors — will become the dominant characteristic of most threats to the U.S.," it warned.